Field of the Invention
This invention relates generally to an option card-equipping device and a computer using the same, and more particularly to an option card-equipping device for improving electromagnetic shielding and a computer using the same by making a contact between a bracket of an option card and a chassis of a main board closer, thereby eliminating an empty space between the above-identified parts.
Contemporary designs in the art are found, for example, in such exemplary references as U.S. Pat. No. 5,004,867 to Mast that discloses a Personal Computer Expansion Slot Seal and Method; U.S. Pat. No. 4,873,395 to Mast that discloses a Personal Computer Expansion Slot Seal and Method; U.S. Pat. No. 4,971,563 to Wells III discloses a Modular Backplane Assemblies for Computers; and U.S. Pat. No. 5,544,008 to Dimmick et al. shows a Computer Expansion Module Apparatus. U.S. Pat. No. 5,036,481 to Lunsford et al. discloses a Personal Computer System with Dual Purpose Expansion Slot; U.S. Pat. No. 4,744,006 to Duffield discloses an Apparatus for Expanding the Input/output Capabilities of a Personal Computer; U.S. Pat. No. 4,924,355 to Mitchell et al. discloses a Personal Computer Having expansion Card adapter Bracket; U.S. Pat. No. 5,204,496 to Boulay et al. discloses an EMI Shielding Gasket; and U.S. Pat. No. 5,650,922 to Ho discloses a Computer Interface Card Mounting Structure. U.S. Pat. No. 5,638,259 to McCarthy et al. discloses an Enclosure for Electronic Modules while U.S. Pat. No. 4,942,380 to Bradford et al. discloses a Housing Assembly Having Flexible Shield and Insulator. Contemporary designs such as that represented by Duffield'006 form a projection on an expansion card bracket and not on the chassis of the main board, while those exemplified by Mast'867 is merely use a groove as a reinforcing element so that a separate part 46 is required to achieve a reduction in electromagnetic interference.
Generally, in a desktop personal computer using one of the designs represented by these references, a connection between a bracket of an option card and a chassis of a main board is performed by connecting a chassis of a main board and a bracket of an option card by a screw. That is, such a connection method using a screw is generally used to connect a main board and an option card. When a surface of a bracket of an option card does not contact closely with a chassis of a main board, it is difficult to shield electromagnetic interference. Also, when a bracket of an option card is bent or a screw is loose and an empty space thereby occurs between a bracket of an option card and a chassis of a main board, the shielding for electromagnetic interference is reduced.
In case of a system using a low frequency clock, this is not a big problem. With a design for a system using a high frequency clock, a high frequency signal may flow out, coupled with an analog signal. Generally, the connection elements are used to increase a contact area between a chassis of a main board and a bracket of an option card. This is not perfect however.